NK’s ground engine test for new hypersonic missile may still need improvement

North Korea has successfully conducted a ground test of a solid-fuel engine for its new intermediate-range hypersonic missile, drawing praise from its leader Kim Jong-un, who stressed the military strategic value of the weapon system, according to state media, Wednesday.

But defense watchers believe it may still need to work on maneuverability even though the technical nature of the missile engine seems to have improved since last November when Pyongyang carried out ground tests of newly developed solid-fuel engines for a new type of intermediate-range ballistic missile (IRBM).

Hypersonic missiles are on the list of sophisticated weapons Kim vowed to develop during a party congress in 2021, along with nuclear-powered submarines, spy satellites and solid-fuel intercontinental ballistic missiles.

The latest missile engine test, which was conducted under Kim’s supervision at the Sohae Satellite Launching Station on the country’s west coast, Tuesday, suggests “progress in North Korea’s efforts to develop a more powerful, agile missile designed to strike faraway U.S. targets in the region,” the North’s official Korean Central News Agency said on Wednesday.

“Speaking of the engine module, the fuel tank has been extended,” said Shin Jong-woo, a senior researcher at the Korea Defense and Security Forum, a think tank. “The combustion duration becomes longer, allowing the engine to withstand high pressure and temperature. However, the successful engine test doesn’t guarantee the successful test of the hypersonic missile. We still need to keep our eyes on the hypersonic glide vehicle.”

Shin explained that the solid-fuel engine can be fueled and remain in storage for a longer period with fewer concerns over corrosion caused by the propellant, and be fired more reliably if needed. Solid fuel offers greater mobility for missiles and reduces launch preparation time.

Experts said North Korea’s latest engine test is not part of its plan to escalate military provocations but to stick to its fiveyear plan for the development of defense science and weapon systems.

“North Korea already carried out ground tests of what it identified as newly developed solid-fuel engines for a new type of IRBM last November and test-fired a solid-fuel IRBM tipped with a hypersonic warhead in its first ballistic missile launch in January,” said Cho Han-bum, a senior researcher at the Korea Institute for National Unification, a state-funded think tank.

“The fact that they are doing more testing suggests that something apparently is not working the way they want.”